The present invention relates to the manufacture of surgical needles for use in surgical sutures and more particularly to an improved method and apparatus for inspecting needle points during the manufacture of drilled taper point needles for surgical sutures.
In the manufacture of drilled taper point needles for use in surgical sutures, wire from a spool is formed into sharpened needle blanks by unspooling the wire in a machine called a Bundgen machine, which cuts the wire into needle blanks of predetermined length. The needle blanks are then introduced into a Schumag machine, which grinds a taper point having a predetermined profile on one end of the needle. The point may require multiple passes on the Schumag machine to obtain the proper configuration. The blanks are then packaged and stored until needed.
The needles are processed by one or more index machines which perform various operations necessary to form a curved needle with a hole of predetermined depth drilled in the barrel end thereof. After the needle is formed, a suture is threaded into the hole, the needle is crimped at the barrel end to attach the needle to the suture and winding, the completed suture is placed in its primary packaging, the primary package containing the suture is sterilized then placed in secondary packaging, and the secondary packaging is inspected before the product is shipped.
For many years, the process for forming a drilled taper point needle required a pair of index machines operating in tandem for carrying out the various operations required to form a tapered point needle. The index machines, actuated by a rotary drive, typically contained space for up to eight stations circumferentially mounted on a circular table. A rotating platform, actuated by a rotary drive, was provided in the center of the table and contained a series of eight chucks circumferentially spaced apart at 45 degree angles. In the first index machine needle blanks were introduced one blank at a time to a rotating chuck, where the blank was successively sheared, a hole was drilled in the barrel end thereof, the hole was inspected and bad needles were rejected. Because not all of the required operations could be carried out on the eight stations of the first index machine, it was necessary to unload the needles from the first machine, wash and dry the semi-finished needles to remove the drill cooling oil and subsequently introduce them into a second index machine where the remaining processing steps could be carried out. On the second index machine, the semi-finished needles were subjected to a series of grinding and polishing stations to finish and retouch the needle point, which was often damaged as the needles were introduced into the chucks in the first or second machines. After further grinding and polishing on the second index machine, the point was inspected, ribs were formed on the needle by a flattening press and the needle was curved to the proper radius and unloaded. The completed needles were then washed and dried again and sent to a static anode for finishing.
In the late 1980s and early 1990s, it was determined that major cost savings could be achieved by the elimination of needle makers and the intermediate steps of degreasing semi-finished needles if the operations of the index machines could be combined into a single machine. Index machines were built and successfully operated in the late 1980s and early 1990s in which the essential functions carried out by the two index machines were combined in a single combined index machine. Unfortunately, one of the stations that had to be eliminated to combine the essential functions into eight stations was the needle point inspection previously employed in the second index machine. While the combined index machines could be operated at significant cost savings and had many other advantages, the elimination of the needle point inspection function from the combined machines did not provide the operators with desired quality control. Accordingly, a need arose for a needle point inspection station in the combined index machines.
The specification discloses an improved needle inspection station for use in a combined index machine for forming drilled taper point needles of the type having a plurality of chucks mounted on a rotating platform adapted to selectively engage and release a needle to be formed, a rotary drive for indexing the platform and the chucks through a plurality of radial positions, and a plurality of work stations circumferentially disposed adjacent the radial positions occupied by the chucks. In accordance with one aspect of the present invention, the needle inspection station includes a base plate, an upwardly extending support member connected to the base plate, a slide member slidably received within the support member and reciprocally movable toward and away from a chuck occupying a position adjacent the inspection station, a gripper for gripping a needle to be inspected, and a needle inspection platform slidably mounted on the baseplate reciprocally moveable toward and away from a chuck occupying a position adjacent the inspection station. The slide member is moveable toward the chuck to permit the gripper to engage the needle, retract it from the chuck and rotate it 180 degrees to reverse the orientation of the needle relative to the chuck. The slide member is then moveable back toward the chuck to allow the gripper to replace the needle in the chuck. The needle inspection platform is moveable toward the chuck to permit the needle point to be tested. The needle inspection platform includes a stop containing a resilient conductive material at the leading edge of the platform and a strip of nonconductive material disposed between the stop and the chuck, such that when the strip is moved into contact with a needle extending from a chuck, a properly formed needle point will penetrate the strip and make electrical contact with the stop, thereby signaling a programmable logic controller connected to the stop that a properly formed needle has been detected.
In accordance with a second aspect of the invention, the specification discloses a method for inspecting the point of a drilled taper point needle formed in a combined index machine of the type having a plurality of work stations circumferentially spaced adjacent the positions occupied by a rotating chuck containing a needle to be formed. At the needle point inspection station, a needle held in a chuck is gripped by a pair of gripper fingers on the barrel thereof. The chuck is then opened and the gripper fingers retract the needle from the chuck barrel and rotate the needle approximately 180 degrees to reverse the orientation of the needle. The gripper fingers then insert the needle back into the chuck with the needle point extending from the chuck and the chuck jaws are closed to hold the needle for inspection. A point inspection platform containing a resilient conductive material and a strip of nonconductive material disposed between the stop and the chuck is then advanced and retracted from the chuck such that a needle with a properly formed point will penetrate the strip of nonconductive material and make electrical contact with the stop. The presence of a current in the stop, indicating that a properly formed taper point has been detected, is recorded by a programmable logic controller for controlling the disposition of needles at a subsequent work station.